Add conceptual model

[LillyG901]

Description of the issue

The ontology does not contain a way to separate the concept, implementation and the representation inside a computer of a model.
(related issue #1953)
The conceptual model should be the part of a model, that specifies variables and relationships within a system boundary.

This is a term needed for modeling uncertainties, more specifically the location of an uncertainty within a model.
See issue #1829

Ideas of solution

The term should be defined similarly to how it is described within this paper to properly work in the needed context.

Workflow checklist

• I discussed the issue with someone else than me before working on a solution
• I already read the latest version of the workflow for this repository
• The goal of this ontology is clear to me

I am aware that

• every entry in the ontology should have a definition
• classes should arise from concepts rather than from words

[stap-m]

@LillyG901 could you cite the relevant part of the paper for finding a definition, please?

[madbkr]

Maybe adding the proposed definition here would be good. This is the current draft from @LillyG901

A conceptual modelis a model that specifies variables and relationships within a system boundary.

[LillyG901]

The conceptual model specifies the variables and relationships inside the boundaries.
The conceptual model gives the interpretation of the computer model (Petersen,
2006). Petersen (2006) has this as a separate category, while Walker et al. (2003)
include it under model uncertainty.

• This is the definition given within the paper.

[madbkr]

I feel like the second sentence The conceptual model gives the interpretation of the computer model. should be part of the definition if we end up adding computer model too. I like how it links those.

[LillyG901]

That's a good idea. Maybe we could add two alternate definitions to conceptual model?
One being the one I proposed and another could be
A conceptual model is a model that gives the interpretation of the computer model

Or we could merge them and define conceptual model in one definition as
A conceptual modelis a model that specifies variables and relationships within a system boundary. It gives the interpretation of the computer model.

We should however, wait for the resolution of #1953. Just in case we don't add computer model at all.
We also need to be careful not to add cyclic defintions, since we could also define computer model as A computer model is a model that implements a conceptual model.

[stap-m]

I feel like the second sentence The conceptual model gives the interpretation of the computer model. should be part of the definition if we end up adding computer model too. I like how it links those.

A conceptual model may provide the interpretation for a (computer) model, or just be a conceptual model on its own. Therefore, we should leave out the extension for conceptual model, in my view. However, I agree to the relation the other way round: a computer model is based on a conceptual model. I already commented on that in #1953.